Can I register for a class after being accepted to a program?

I was trying to sign up for a Comm 102 class after being accepted to a program. When I got accepted to that program, I remember receiving an email informing me that I wouldn't be able to register for classes. I thought that was about the program specific courses, not the general courses like English etc. Since I have some time until Fall, I was trying to complete Comm 102, but I was getting " Student Status prevents registration" error when tried to. Any ideas? Thank you.